Considering the expense, precision and difficulty of manufacturing computer chips, you would think the engineers designing them are pretty serious people.

But it’s not all business inside a chip fab, as these microscope photos reveal. In fact, the designers of microchips frequently hide tiny cartoons, drawings and even messages alongside the super-tiny circuits and semiconductors they create.

Chipworks, a company that analyzes microchips by peeling them apart and looking at them under microscopes, has discovered many examples of silicon art. We’ve selected a few highlights here from the firm’s extensive galleries of silicon art, but check the Chipworks website for more.

The images in this gallery are magnified 200 to 500 times.

As Chipworks explains, these drawings are made with the same processes used to assemble the rest of a computer chip. Designs are etched onto photolithography plates which are then used to “print” the chips’ circuitry, layer by layer, in thin films of silicon, silicon dioxide, aluminum and other materials. It’s a complicated process that takes hundreds of steps and millions of dollars worth of machinery, and it requires incredible degrees of precision and repeatability.

But if there’s a little unused space in a chip, why not fill that with an entertaining design? It’s not as if most of the chip companies’ customers will ever notice. The only people likely to see these designs are the chip engineers’ supervisors and analysts at companies like Chipworks.

“The mass production of these works of art as parasites on the body of a commercial IC goes unnoticed by most observers,” writes Chipworks. “Their existence is a tribute to human resourcefulness and creativity, surfacing from deep within a complex process.”